NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005




Synonyms & Trade Names

1,4-Dimethylbenzene; para-Xylene; p-Xylol
DOT ID & Guide
1307 / 130


NIOSH REL: TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3)
OSHA PEL: TWA 100 ppm (435 mg/m3)
900 ppm See: 95476
1 ppm = 4.41 mg/m3
Physical Description
Colorless liquid with an aromatic odor. [Note: A solid below 56°F.]
MW: 106.2
BP: 281°F
FRZ: 56°F
Sol: 0.02%
VP: 9 mmHg
IP: 8.44 eV

Sp.Gr: 0.86
Fl.P: 81°F
UEL: 7.0%
LEL: 1.1%

Class IC Flammable Liquid: Fl.P. at or above 73F and below 100F.
Incompatibilities & Reactivities

Strong oxidizers, strong acids
Measurement Methods
NIOSH 1501, 3800; OSHA 1002
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet (flammable)
Change: No recommendation

First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Soap wash promptly
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations
Up to 900 ppm:
(APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)*
(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)*
(APF = 10) Any supplied-air respirator*
(APF = 50) Any self-contained breathing apparatus with a full facepiece
Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister/Any appropriate escape-type, self-contained breathing apparatus
Important additional information about respirator selection
Exposure Routes
inhalation, skin absorption, ingestion, skin and/or eye contact
Irritation eyes, skin, nose, throat; dizziness, excitement, drowsiness, incoordination, staggering gait; corneal vacuolization; anorexia, nausea, vomiting, abdominal pain; dermatitis
Target Organs
Eyes, skin, respiratory system, central nervous system, gastrointestinal tract, blood, liver, kidneys
See also: INTRODUCTION   See ICSC CARD: 0086   See MEDICAL TESTS: 0243